[llvm] [LoopInterchange] Require unordered load/store (PR #146143)

[Ryotaro Kasuga via llvm-commits]

https://github.com/kasuga-fj commented:

Could you please add tests?

Also, IIUIC, `isSimple` imposes a strictly stronger condition than `isUnordered`.  If the opposite were true (i.e., if DA required a stronger restriction than `isSimple`), this change would make perfectly sense to me. However, that is not the case here. So, it might be meaningful to call `isSimple` instead of `isUnordered` here (I feel like there's not a particularly strong reason, but I'm not entirely sure).

https://github.com/llvm/llvm-project/pull/146143